Determination of structure, sequence, binding sites, affinity contents and capacity for human and rat ligandin and Z isolated from liver, kidney and small intestine as regards various organic anions of biological and clinical importance. Continue immunofluorescent localization of ligandin and Z in human and rat tissues with application of ferritin-conjugated and peroxidase-conjugated antibody permitting subcellular localization of these proteins. Application of a newly developed radioimmunoassay for measurement of ligandin and Z in human liver, kidney and small intestinal biopsy specimens permitting study of relationship of disease processes to these proteins. Study of the role of ligandin in renal and intestinal organic anion transport and its function as a GSH transferase. Localization of Z protein in plasma membrane from various tissues and further characterization of its role in fatty acid transport and esterification. Continued study of the inheritance and pathogenesis of various types of familial jaundice in man including recurrent jaundice of pregnancy, Gilbert's syndrome, Dubin-Johnson syndrome, Rotor syndrome and organic anion "storage" disease" using newly developed tests of heterozygocity. Purification and functional characterization of UDP glucuronyl transferase. BIBLIOGRAPHIC REFERENCES: Arias, I.M. and Jansen, P.: Protein Binding and Conjugation of Bilirubin in the Liver Cell. In JAUNDICE ed. C.A. Goresky and M.M. Fisher Plenum Press, 1975. Kirsch, R., Kamisaka, K., Fleischner, G., and Arias, I.M.: Structural and Functional Studies of Ligandin, A Major Renal Organic Anion Binding Protein. J. Clin. Invest. 55: 1009, 1975.